Startup interisland airline go! — a subsidiary of Phoenix-based Mesa Airlines — has extended its $29 one-way fare through the end of the year. Veteran competitors Aloha Airlines and Hawaiian Airlines quickly matched the offer. Some restrictions apply, of course, and the sale prices are available only through Friday. This latest volley in Hawaii's air war comes as go! released its traffic figures for July, showing a decline in passengers since June — its first month of business. The new airline's load factor fell to 73 percent from 83 percent, although according to Pacific Business News, the lower figure is more in line with industry norms and estimates by Aloha. Hawaiian reported its planes were 89 percent full in July.

Travelers are seeing prices they haven't seen for decades as go! continues to challenge Aloha and Hawaiian for a slice of the interisland market. At one point, go! offered tickets for $19, a fare that Hawaiian matched but that Aloha countered with a 1,000-ticket free givaway.

While $29 tickets aren't sustainable in the long-term — and as critics continue to charge go! with predatory pricing practices — residents are certainly taking advantage of the fierce competition, many traveling interisland for the first time since ticket prices skyrocketed after Sept. 11. One-way fares had surpassed $100, and travelers prone to booking at the last minute would find a trip to Las Vegas more affordable.

Still, tickets at today's sale prices are limited, and as of this morning, the $29 seats on several flights were already sold out.